As for the formulations of agricultural chemicals (pharmaceutical compositions) or the like, in some cases, dyes are added to the formulations from the viewpoint of easier discrimination of formulations, prevention of misingestion, or the like.
Such dyes are organic colorants, which are generally unstable against light or heat.
For the powdered or particulate formulations, a solid substance in the formulation acts as a covering to protect against the light, and thus there is only a very small possibility of there being a problem in terms of the stability of the dye against light.
However, in the liquid formulations containing no solid, even in the case of using a light-resistant container, or the like, slight penetrated light frequently decomposes the dye in many cases. Further, in a case where a liquid formulation containing a dye is kept at a high temperature over a long period of time, the dye is decomposed by heat in some cases. In addition, in such a case, a liquid composition having an original color tone can not be obtained, and further, a product from the decomposition of the dye causes adverse effects on the efficacy in some cases.
Relating to the present invention, Patent Document 1 describes a formulation containing a: an agonist or antagonist of the nicotinic acetylcholine receptors for insects, b: water, c: non-cyclic alcohols, d: coloring agents, and the like, in predetermined ratios.
However, this document has no description on the selection of a solvent to be used to enhance the stability against light and/or heat of the coloring agent.
Furthermore, Patent Document 2 describes a formulation for percutaneous control of parasitic insects and mites against humans, which has the composition as follows: (i) an agonist or antagonist of the nicotinic acetylcholine receptors of the insects at a concentration of 0.0001 to 20% by weight, based on the total weight of the formulation; (ii) a solvent in a group of cyclic carbonate esters at a concentration of 2.5 to 99.9999% by weight, based on the total weight of the formulation; (iii) in some cases, other solvents in a group of alcohols at a concentration of 0 to 95% by weight, based on the total weight of the formulation, and (iv) in some cases, other auxiliary agents selected from the group consisting of a thickening agent, a spreading agent, a coloring agent, an anti-oxidant, a swelling agent, a preservative, a tackifier, and an emulsifier at a concentration of 0 to 30% by weight, based on the total weight of the formulation.
However, the formulation (composition) as described in this document contains no water. Furthermore, this document has a description indicating that a coloring agent may be contained in the formulation, but has no disclosure on a specific example showing that a coloring agent is added to the formulation.
[PATENT DOCUMENT 1] Japanese Patent Application Publication No. 2002-503682
[PATENT DOCUMENT 2] Japanese Patent Application Publication No. 2000-509023